or me, the .30-06. .308 if i want use of a modern battle rifle.
I used to agree to this. I bought my rifles that way.
I then took a long hard look at the situation and realized that "modern battle rifle" meant the last .308 designed for it was the AR10. Since then all the real modern battle rifles have been intermediate cartridges, and they can all take down 200 pound humans out to 500m on the battlefield easily enough.
In an all around catagory, you have to give up something to get something. The first that I considered was that the rifle itself had to be all around. I didn't want to be boxed into a bullet launcher that actually impeded me in shooting.
All manual actions are less ergonomic when repeated shots are required. Self loading actions are superior. To fit the all around definition, it has to be better at different kinds of shooting, no inherently worse.
Given a particular type of action and it's costs, that left the AR15, and given the choices of cartridges in it, the 6.8SPC is the better all around performer. It's got twice the foot pounds of force out to 500 than 5.56, the same muzzle velocity from a four inch shorter barrel, ammo is no more expensive than .308 or other civilian rounds. It can be reloaded, and the components are mainstream. I can also buy it off the shelf.
In the AR15, the combination makes for a gun capable of downing four legged game up to 500 pounds - the Inuit use 5.56 on caribou, the 6.8 has plenty of power. It may not be dangerous game capable, but it's implied you only have one choice, then hunting rabbit with a .458 Socom isn't all that good, either. All around.
Of course, pro poachers do ok with the .22, so justification of a much larger, older, and obsolete military cartridge unsuitable for most soldiers is a bit of a stretch. Which is why I sold off the .308 and don't use the .30-06 any more. I have chosen an all around cartridge, and it's working for thousands of us, too. It IS a truly modern battle rifle cartridge that is used in a truly modern battle rifle, something that doesn't use wood or have an iron receiver. We haven't issued those rifles in the service new since 1963 - we issue composite stocked rifles with aluminum receivers. That is the modern standard until we catch up with all the recent innovations in polymer guns that are now being issued overseas.
And if I need to update it, I can, changing the furniture isn't rocket science. Parts are extremely available from many sources and they all fit properly without gunsmithing.
All around - hunting, home defense, or just sitting there looking purposeful. It's not yer grandpa's poodle shooter any more.